I recently purchased a 2-8-0 DCC on board Bachman locomotive that runs very nice and quite.  It is actually belt driven between the motor and the worm gears. The tender is already set up for speaker installation.  The decoder is in the tender.  Questions= 10 Can I install sound? 2) What do I need to
get to install? 3) Can I install with out soldering or and major changes to existing equipment? 
Thanks Jim